Pectoralis major flap - Vula - University of Cape Town

OPEN ACCESS ATLAS OF OTOLARYNGOLOGY, HEAD &
NECK OPERATIVE SURGERY
THE PECTORALIS MAJOR FLAP
The pectoralis major flap comprises the
pectoralis major muscle, with or without
overlying skin, and may include the underlying
ribs. It has an axial blood supply, and
is based superiorly on the pectoral branch
of the thoracoacromial artery.
Johan Fagan
Deltoid
Pectoralis major: clavicular
head
Pectoralis major: sternocostal
head
It is very useful in the head and neck, and
can inter alia be used for the following:
reconstruction of soft tissue defects of the
oropharynx, oral cavity, hypopharynx, and
skin of the neck; to augment pharyngeal
repairs following salvage laryngectomy
following previous chemoradiotherapy,
and to cover carotid or jugular vein
blowouts etc. Rib may be included to
bridge mandibular defects.
Figure 1: Superficial dissection
Serratus anterior
Relevant Anatomy
Pectoralis major muscle (Figure 1)
Pectoralis major: sternocostal
head
Pectoralis major: clavicular
head
This muscle originates from the anterior
aspect of the medial half of the clavicle;
from the anterior surface of the sternum;
from the cartilages of all the true ribs and
from the aponeurosis of the abdominal
external oblique muscle. The muscle fibers
converge toward its insertion on the
humerus. Muscle fibres arising from the
clavicle pass transversely, and are often
separated from the rest of the muscle by a
slight gap. The remainder of the muscle
courses superolaterally.
Deep relations of pectoralis major muscle
(Figure 2)
Deep to the pectoralis major muscle is its
vascular pedicle, the pectoralis minor
muscle, the costal cartilages, and inferiorly
the costal attachments of the external
oblique muscle.
Figure 2: Deep relations of pectoralis
major muscle
Blood supply of pectoralis major flap
(Figures 2, 3)
Pectoral branch of thoracoacromial
artery
Lateral thoracic artery
Pectoralis minor
The pectoralis major flap is an axial flap
and is based primarily on the pectoral
branch of the thoracoacromial artery and
its accompanying veins. The thoracoacromial
artery is a branch of the axillary
artery, itself a continuation of the subclavian
artery. The pectoral branch of the
thoracoacromial artery courses within a
well-defined fascial plane on the deep

Thoracoacromial a
denervated muscle loses bulk with time
which might be advantageous or disadvantageous,
depending on the functional
and cosmetic objectives of the flap.
Pectoral branch
Pectoralis major
Pectoralis minor
Figure 3: Blood supply of pectoralis major
flap
surface of the pectoralis major muscle
(Figures 2, 9). There is a clear dissection
plane between this fascial layer and the
superficial aspect of the pectoralis minor
muscle making it possible to strip the
pectoralis major and its blood supply off
the pectoralis minor with blunt finger
dissection. Additional blood supply arises
medially from the internal mammary
artery, and laterally from the long thoracic
artery, branches of which are generally
sacrificed during elevation of the flap to
secure adequate pedicle length. Care has to
be taken should the skin island be located
distally in the region of the costal margin
at, or beyond, the lower extent of the
pectoralis major muscle, as the blood
supply then becomes random as opposed to
axial, making perfusion of the flap less
reliable.
Flap design
The flap may be employed either as a
muscular or musculocutaneous flap, with
or without the 4 th or 5 th ribs. The following
discussion will focus on raising a
musculocutaneous island flap.
Positioning, prepping and draping
The patient is placed in a supine position
with the chest exposed and prepped up to
the midline, and inferiorly to the costal
margin. The upper arm is abducted slightly
to expose the anterior axillary fold and
lateral chest wall.
Surface markings of vascular pedicle
The surface markings of the vascular
pedicle are determined by drawing a line
from the shoulder to the xiphisternum and
another line vertically from the midpoint of
the clavicle to intersect the 1 st line (Figure
4).
Innervation
The pectoralis major is innervated by the
lateral pectoral nerve which can be located
just inferior to the clavicle with the
pectoral branch of the thoracoacromial
artery. The medial pectoral nerve passes
through the pectoralis minor muscle and
sends 2 to 3 branches to the pectoralis
major. All these nerves are normally
divided during elevation of the flap. The
Figure 4: Surface markings of pectoral
branch of thoracoacromial artery
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Skin paddle design
The skin paddle is positioned over the
pectoralis major muscle along the course
of the pectoral branch of the thoracoacromial
artery (Figures 4, 5, 6). In order
to ensure that the pedicle is of adequate
length, the distance between the top of the
skin paddle and the inferior edge of the
clavicle should equal or exceed the
distance between the recipient site for the
flap and the inferior edge of the clavicle. In
women the paddle may be placed in the
inframammary crease to include skin on
either side of the crease, so as to avoid
excessive bulk from breast tissue and for
cosmetic reasons (Figure 5).
surface of the pectoralis major muscle. As
the vascular pedicle is located deep to the
muscle, this may be quickly and safely
performed using the bovie / monopolar
diathermy. Care has to be exercised not to
undercut the skin paddle, but rather to
bevel the dissection radially so as to
include as many myocutaneous perforators
as possible that supply the skin paddle
(Figure 6). The skin paddle is tacked to the
underlying pectoralis major muscle with a
few sutures so as to minimise the risk of
shearing injury to the myocutaneous perforators
(Figure 7).
Figure 5: Inframammary skin paddle
Should additional pedicle length be
required, the flap may be extended up to
2.5cms beyond the pectoralis major muscle
inferiorly at the costal margin, with the
knowledge that the flap then becomes a
random pattern flap and the blood supply
more tenuous.
Elevation of skin paddle
The skin is incised around the skin paddle,
and the dissection is extended onto the
Figure 6: Dissection of skin paddle onto
pectoralis major muscle, and incision
along anterior axillary fold
Exposure of pectoralis major muscle
An incision is extended laterally from the
peripheral margin of the skin paddle along
the anterior axillary fold, which corresponds
with the lateral margin of the pectoralis
major muscle (Figure 6). The skin
and breast tissue above the skin paddle is
then widely elevated from the pectoralis
major muscle with diathermy up to the
clavicle (Figure 7).
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surface of the pectoralis major muscle
(Figure 9).
Figure 7: Exposure of pectoralis major
muscle pedicle
Elevation of pedicle
The pectoralis major muscle is incised with
cautery medially and inferiorly to the skin
paddle, and is dissected from the ribs and
intercostal muscles. The muscle is not
divided superior to the skin paddle, as this
might divide the vascular pedicle.
Figure 8: Elevating pectoralis major from
pectoralis minor along lateral margin of
muscle
The pectoralis major muscle is then freed
alongside the sternum with cautery. During
this dissection perforators from the internal
mammary artery are transected and
cauterized.
The dissection plane between the pectoralis
minor and major muscles and the
vascular pedicle is found by dissecting
along the lateral border of the pectoralis
major muscle with electrocautery (Figure
8). Once this intermuscular plane has been
identified, one can readily free the pectoralis
major and its vascular pedicle from the
pectoralis minor by stripping with a finger
towards the clavicle (Figure 8). This
brings the vascular pedicle (pectoral
branch of thoracoacromial artery) clearly
into view within the fascia on the deep
Figure 9: Vascular pedicle visible on deep
aspect of pectoralis major muscle
The pedicle is kept in view and protected
from injury while the branches from the
lateral thoracic artery, and the branches of
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the medial pectoral nerve that traverse the
pectoralis minor and enter the deep surface
of the flap, are divided. The pectoralis
major muscle is divided lateral to the
pedicle while keeping the pedicle in view,
thereby freeing it from the humerus.
Skin tunnel over clavicle
The flap is generally passed into the neck
superficial to the clavicle through a wide
subcutaneous tunnel (Figure 10). The
tunnel should be large enough to permit
easy delivery of the flap into the neck
without shearing the musculocutaneous
perforators supplying the skin paddle, and
to avoid strangulating the vascular pedicle.
Dividing the subdermal connective tissue
fibers of the skin above the skin tunnel
with an upturned scalpel is a helpful
adjunct to gain additional space.
Figure 11: Check that pedicle is not twisted
major muscle just below the clavicle,
taking great care to preserve the vascular
pedicle (Figure 12). An infraclavicular
segment of muscle may also be excised.
This has the benefit that the pedicle is
directly applied to the clavicle, without
intervening muscle. It has the added bonus
of avoiding an unsightly, bulky pedicle
over the clavicle. The 2 nd maneuver to gain
additional length is to pass the flap behind
the clavicle.
Figure 10: Flap is passed over the clavicle
though a wide skin tunnel
After passing the flap into the neck, check
that the pedicle is not twisted (Figure 11).
Gaining additional length
In the event that the pedicle is too short,
two manoeuvres may add additional
length. The 1 st is to transect the pectoralis
Figure 12: Vascular pedicle visible
following division of muscular pedicle.
Closure of donor site defect
The donor site is either closed primarily
with a closed suction drain, or a split skin
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graft is applied. Primary closure may be
facilitated by undermining the surrounding
skin.
pectoralis major flap interposed between
oropharynx and gastric pull-up that was
too short to reach oropharynx
Some Clinical examples
Figure 13: Reconstruction following total
glossectomy
Figure 16: Reconstruction of (a) pharyngocutaneous
fistula with (b) pectoralis
major muscle flap and (c) split skin graft
and (d) final result
Figure 14: Augmentation of pharynx with
pectoralis major myocutaneous flap following
total laryngectomy with partial
pharyngectomy
Figure 17: Reconstruction following segmental
mandibulectomy and resection of
tonsil, soft palate, and base of tongue
Video of pectoralis major flap (University of
Iowa, USA)
Author & Editor
Figure 15: Laryngopharyngoesophagectomy
defect reconstructed with tubed
Johan Fagan MBChB, FCORL, MMed
Professor and Chairman
Division of Otolaryngology
University of Cape Town
Cape Town, South Africa
johannes.fagan@uct.ac.za
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THE OPEN ACCESS ATLAS OF
OTOLARYNGOLOGY, HEAD &
NECK OPERATIVE SURGERY
www.entdev.uct.ac.za
The Open Access Atlas of Otolaryngology, Head & Neck
Operative Surgery by Johan Fagan (Editor)
johannes.fagan@uct.ac.za is licensed under a Creative
Commons Attribution - Non-Commercial 3.0 Unported License
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